BIL used to be sherriff here. His hobby was finding pot patches. The National Guard flys everything here late summer and uses some camera that IDs pot from the color. BIL says it can spot single plants. They would locate them and map all the plantings and he and his deputies would go pull it up. They had a picture in the paper one time burning a huge pile of it and you couldn't see 2 of the deputies faces because they were standing down wind in the smoke. I bet they were smiling.